However the more you use K2, the more you understand that its not ready to be applied on professional websites so far for the following reasons.
1. Support of K2 do not Exists (Do not bother by sending the developers technical requests as they will not answer) "I hope the developers will not get offended by that, instead they should answer the 100's of unattended posts in their forum"
2. Compatibility issues with Internet Explorer, K2 has many limitations with Internet explorer and in many cases the content will get damaged, i highly advice designers/developers to check the site on Internet Explorer to avoid serious embarrassment.
3. Adaptability issues: This is not an error but a limitation in K2, as K2 contains so far single format to display the content ie. if you want to publish the article image on right side and header and content on left side in Category view, you have to manually hardcore modify the CSS files to be able to do that!
4. Simplicity : Again the main success of any software is the simplicity, although K2 has a very powerful, yet easy interface however when you want to adapt it to you design/Template/Business requirements its difficult.
To sum all that up, i will say that K2 is a very powerful project, but i will not yet advice to use it in any serious business site as it should be yet beta version.